Serum samples collected at baseline were analysed for serum total IgE as well as serum specific IgE against four inhalant allergens (birch, grass, cat, and house dust mite (Dermatophagoides pteronyssinus)) by using the Immulite® 2000 Allergy Immunoassay System [9], [10].
Specific IgE was measured against Dermatophagoides pteronyssinus, timothy grass, cat and Cladosporium herbarum.
Blood samples from all participants were analysed for specific IgE against the four most clinically important allergens in Denmark, i.e. birch, grass, cat and house dust mite.
Throughout, adjustments for age, sex and sensitisation to the allergens not under assessment (four of house dust mite, grass, cat, Alternaria and birch) were included.
Specific IgE levels were measured with the Pharmacia CAP System [ 26], and atopy was defined as assay results > 0.35 kU/L for any of the following allergens: house dust mite (Dermatophagoides Pteronyssinus), timothy grass, cat and mould (Cladosporium Herbarum).
There were 1888 subjects who showed a positive SPT to at least one of six allergens with the highest prevalence of positive reactions (hazel, birch, grass, cat, dog, and Dp; the reactions to the two mites were concordant in 80%).
Baseline serum samples were analysed for serum specific IgE against the four most clinically important inhalant allergens in Denmark: birch, grass, cat, and the house dust mite Dermatophagoides pteronyssinus, using the ADVIA Centaur Specific IgE assay [ 28].
Analyzed blood samples within the ECRHS II study were used to determine if the participants had atopy (defined as total IgE >100) and if they had a specific IgE to house-dust mite, grass, cat, and/or Cladosporium radioallergosorbents test (RAST).
A previous analysis of 50 plasma samples from school children living in the study area of specific IgE for D. pteronyssinus, P. americana, rye grass, cat, and Aspergillus showed that none of the children negative for D. pteronyssinus and P. americana were positive for any of the other allergens (Cooper PJ et al., unpublished data).
